The Obama administration is selectively enforcing immigration laws depending on the gender of the illegal alien and which country he or she is from, according to new government data that shows Mexicans are getting special treatment.

Obtained by a nonprofit university group dedicated to researching the U.S. government, the records reveal a surprising variability in immigration detainer trends by gender and nationality. Detainers are notices issued by Immigration and Customs Enforcement (ICE) asking local law enforcement agencies to hold suspected illegal immigrants until the federal agency takes them into custody, presumably to deport them.

It’s part of a federal-local partnership in which local police agencies identify deportable criminal aliens that then get reported to ICE. Municipalities that offer illegal immigrants sanctuary refuse to contact federal authorities and often release the offender back into the community. Last spring Judicial Watch sued Cook County in Illinois challenging its refusal to honor ICE detainers, instead releasing as many as 1,000 criminal aliens sought by the agency.

It turns out that even when the agency is notified it’s selectively enforcing the law. Among the sharpest declines in the use of detainers was against individuals identified as born in Mexico, the government records show. The data spans from October 2011 to August 2013 and reveals a decline of 25% in detainers issued against Mexicans as well as a decrease of 32% in detainers issued against women and a 22% drop against men. Some countries, such as Laos and Haiti saw an increase of 12% and 9% respectively, but the total number of immigrants from those countries is tiny.

The university research center, Transactional Records Access Clearinghouse (TRAC), obtained the information through public records laws as part of an ongoing series about ICE detainer practices. The data also reveals that the overall number of detainers issued by ICE has dropped by nearly a quarter since fiscal year 2012 and that enforcement varies drastically by region. For example ICE agents in the Buffalo area issued 78% more detainers while agents in the Miami Florida area issued 33% fewer.

In the case of Mexicans, the enforcement decline is quite sharp in a very short period. The monthly average number of illegal aliens from Mexico issued ICE detainers dropped from 16,511 in the first part of fiscal year 2012 to 13,302 a month later and 12,413 at the start of fiscal year 2013, the data shows. Other countries—such as Brazil and India—saw similar decreases percentagewise, but they don’t compare because the overall number of immigrants from each is only in the double digits.

Mexico is by far the country that sends the most illegal aliens to the U.S. and the Obama administration has entered into a number of agreements to protect its nationals. A few years ago the Department of Labor (DOL) signed an accord to protect Mexican migrants and last year the federal agency that enforces the nation’s workplace discrimination laws, the Equal Employment Opportunity Commission (EEOC), penned a contract vowing to prevent workplace discrimination against illegal aliens from Mexico while educating them about their civil rights.

The administration has also given Mexico unprecedented say in U.S. matters, including immigration enforcement and our judicial system. A few years ago President Obama actually asked the Supreme Court to halt the execution of a Mexican illegal immigrant convicted of bludgeoning, raping and murdering a teenage girl following a written order issued by Mexico. The country has no death penalty and refuses to extradite criminals who flee the U.S. unless prosecutors assure they won’t seek capital punishment.

Last fall the Mexican Camara de Diputados, which is similar to the U.S. House of Representatives, passed a measure commanding American officials to free three foreign intelligence officers convicted of espionage and conspiracy to commit murder. The spies, agents of Cuba’s communist government, were convicted in 2001 and have lost various appeals. They ran a network (La Red Avispa) that surveilled vulnerable entry ports to import arms and explosives into the U.S., penetrated anti-communist groups in Florida and infiltrated the U.S. Southern Command, the Defense Department’s operation responsible for military activities in central and South America.